People who want to communicate in languages they do not speak have several options. They can hire human interpreters who can speak and understand both the language of their employers (the source language) as well as the language their employers wish to communicate in (the target language). An interpreter listens to the speaker communicate a message in the source language, and then translates by communicating the message in the target language. This option suffers from several drawbacks: interpreters may be prohibitively expensive or otherwise unavailable, or may purposely translate inaccurately if their objectives are at odds with those of the speaker. Another option, popular with many tourists, is to use a translation phrasebook. This allows speakers to look up common words and phrases in their native language, and provides a phonetic translation of the phrase in the target language. However, this option suffers from the drawback that it takes a significant amount of time to look up a word or phrase, making for exceedingly slow communication.
The inadequacies of the above translation options have led to the development of electronic translation devices that provide nearly instantaneous translations. For example, U.S. Pat. No. 6,434,518, incorporated herein by reference, discusses an electronic translator that functions like an enhanced translation phrasebook. A user selects one of a number of predetermined words or phrases in a source language, the selected word or phrase is translated into a target language, and an audio output is provided to pronounce the selected word or phrase in the target language. While this solution may be faster than using a phrasebook, it is still slower than using a human interpreter because the word or phrase that is to be translated must still be found and selected from among many available words and phrases. Furthermore, the vocabulary may be limited where a broad vocabulary or a situation-specific vocabulary is needed.
European publication no. EP 751467, incorporated herein by reference, discusses an electronic translation device that functions more like a human interpreter. A user speaks a phrase in the user's native language, and the device provides an identical or similar phrase or sentence in the user's native language. If the phrase or sentence provided by the device is that intended by the user, the user can operate a control key and a corresponding phrase or sentence is output by the device in the target language. With other similar electronic translation device, a user can speak a phrase in the user's native language, and the translation device will repeat the phrase in the target language through an audio output. A match is made between the spoken native language phrase and similar native language phrases stored in the device if the spoken phrase and similar phrase are similar enough as measured by some predetermined standard. Such devices allow more rapid communication than an electronic or paper phrasebook translator, but unfortunately are not as reliable as might be desired. These devices cannot recognize the speech of an arbitrary user, and thus must be trained using speaker-dependent voice recognition techniques known in the art. Therefore, such a translation device may only be used by a single user who has trained the device.
There is thus a need in the art for fast and reliable translation methods and devices that need not be trained and yet accurately recognize spoken phrases in a source language and provide correct translations into a target language.